Baby acne is usually seen on the cheeks, chin, and forehead. It can be present at birth but usually develops around 3 to 4 weeks of age. Baby acne occurs when hormonal changes in the body stimulate oil glands in the baby's skin. The condition can look worse when the baby is crying or fussy, or any other instance that increases blood flow to the skin. Baby acne is harmless and usually resolves on its own within several weeks.